The Last Gospel is the name given to the Prologue of St. John's Gospel (John 1:1–14) when read as part of the concluding rites in the Tridentine Mass. The Prologue speaks on Jesus Christ as the Logos and on the Incarnation.
The Last Gospel began as a private devotional practice on the priest's part, but was gradually absorbed into the rubrics of the Mass. Immediately after the blessing the priest goes to the Gospel side of the altar.
He begins with the Dominus vobiscum as at the Proclamation of the Gospel during Mass; however, since he reads from an altar card, he makes a Sign of the Cross with his right thumb on the altar's surface instead of the Gospel text, before signing his own forehead, lips, and chest. At the words "Et Verbum caro factum est" ("And the Word became flesh"), the priest (and, if present, the congregation) genuflects.
The text of John's Gospel is perhaps best known for its opening, "In principio erat Verbum, et Verbum erat apud Deum, et Deus erat Verbum," which in most English translations has been rendered as "In the beginning was the Word, and the Word was with God, and the Word was God."
The third Mass of Christmas Day, where this same Gospel is read as the Gospel of the Mass, has no Last Gospel; before 1954, the Gospel for the Feast of the Epiphany would be read here. Also, a superseded Mass, e.g. a Saint's feast superseded by a Sunday, could be commemorated by, among other things, having its Gospel as the Last Gospel.